Shehzad, 22, scored a career-best 176 but was dismissed in the last over before lunch, hit wicket off New Zealand's seamer Corey Andeson.
Shehzad attemped a hook but missed the ball which hit him on the side of the temple. He fell and as he did so, his bat hit the stumps for a hit-wicket dismissal.
Shehzad felt dizzy and had to be helped off the field by team physio Brad Robinson.
He was rushed to a hospital where a scan revealed a minor fracture.
"The specialist surgeon has confirmed minor fracture and has advised 48 hours of close monitoring. In case the pain doesn't subside than the surgeon may opt for decompression", said team manager Moin Khan.